1. Field of the Invention
The invention generally relates to an image processing system and an image processing apparatus.
2. Description of the Related Art
There is a technology known in the art in which plural image processing apparatuses are connected such that, when one image processing apparatus receives a FAX transmission job that the image processing apparatus may not be able to carry out by itself, the image processing apparatus may request other image processing apparatuses connected to it to carry out such a FAX transmission job. For example, in such a technology, one image processing apparatus having no FAX function (hereinafter called a “master machine”) connects to another image processing apparatus having a FAX function (hereinafter called a “slave machine”) such that a document read by the master machine is FAX transmitted by the slave machine connected to the master machine.
However, in this example, an upper limit of one FAX operation conducted by the slave machine is predetermined so that a new job may not be carried out if the operation of the new job exceeds the upper limit of the FAX operation. The upper limit is set for the FAX operation to prevent a storage region for the FAX transmission function from receiving jobs that may exceed its capacity, because the storage region needs to store FAX transmission condition information such as an address or image information every time a new job is assigned. Note that the FAX transmission condition information and the image information contained in a job are hereinafter simply called “job information”).
In such collaborative FAX transmission, since each of the master machine and the slave machine includes a storage region, such a master-slave model may carry out the number of FAX transmissions more than the number of FAX transmissions carried out by a stand-alone FAX machine. Japanese Patent Application Publication No. 2002-290647 discloses an example of the master-slave model configuration in which a master digital copier reads a document image, transfers the read document image to a slave digital copier having a FAX function, and requests the slave digital copier to fax the transferred document image.
However, it may not be efficient for FAX transmission scheduling to simply carry out specific jobs in corresponding apparatuses. The FAX transmissions are generally carried out based on the round-robin job scheduling. The round-robin job scheduling differs from sequential job scheduling where jobs are processed in the job-introduced order. Specifically, in the round-robin job scheduling, job requests are transmitted in the address order from respective first addresses in different job queues. That is, after all job requests corresponding to the first addresses in the different job queues are transmitted, and job requests corresponding to the second addresses are transmitted. The job information is distributed between the master machine and the slave machine in the master-slave model. However, in such round-robin job scheduling, when the slave machine needs to transmit a job request (i.e., when a transmission turn of a job request comes) but the appropriate job information corresponding to the job request is not readily available (i.e., not stored) in the slave machine, the slave machine may not be able to transmit the job request to a corresponding address due to lack of the necessary information in the slave machine.